1. Field of the Invention
In general, the present invention relates to a microbead automatic recognition method and microbeads used in the microbead automatic recognition method. To put it in detail, the present invention relates to a microbead automatic recognition method for acquiring information on the rear/front and/or orientation of a microbead on the basis of the positions of a plurality of reference points created on the microbead in an operation to read a recognition pattern also created on the microbead and relates to microbeads used in the microbead automatic recognition method.
2. Description of the Related Art
In a biochemical analysis in the past carried out on an analysis subject such as nucleic acid or protein, a particle-state carrier referred to as a microbead is used. In a biochemical analysis in the past carried out on nucleic acid for example, a microbead having a probe nucleic-acid chain solidified on the surface of the microbead is used and, on the basis of interactions between the probe nucleic-acid chain having a base array complementary to a target nucleic-acid chain and the target nucleic-acid chain probe, the target nucleic-acid chain is separated. In a biochemical analysis in the past carried out on protein, on the other hand, a microbead having an antibody solidified on the surface of the microbead to serve as an antibody against a target protein is used to separate the target protein in the same way as the biochemical analysis in the past carried out on nucleic acid.
In recent years, in biochemical analyses each making use of these microbeads, an even higher throughput is demanded. In response to the demand, a technology for increasing the speed of the analysis has been developed.
For example, claim 23 described in Japanese Patent No. 3468750 (herein after referred to as Patent Document 1) states: “A method for detecting an analyte recognized by an analysis reactant of the analyte among a number of analytes in a sample, said method comprising the steps of:
(a): bringing a number of groups of fluorescent particles each having at least one nano-particle on the surface of said fluorescent particle and each labeled by its fluorescent dye into contact with said sample wherein said group includes fluorescent particles each having a fluorescent signal varying from group to group and an analysis reactant also varying from group to group and said analysis reactant is linked peculiarly to one analyte in said sample;(b): adding said sample to a label reagent;(c): analyzing said fluorescent particle showing that said analysis reactant is linked peculiarly to one analyte in said sample by detection of said label; and, at the same time,(d): determining a group of said fluorescent particles linked to their respective analytes from a function of said varying fluorescent signal associated with one of said groups.”
In accordance with Suspension Array Technology proposed by Luminex Corporation on the basis of the technology described above, a microbead is labeled with two types of fluorescent pigment by giving a change to the color of emitted light so that microbeads of up to 100 types can be recognized. In accordance with Suspension Array Technology, by solidifying a probe nucleic-acid chain peculiar to a microbead and an antibody peculiar to a microbead on the microbead of each of 100 different types, in one analysis, nucleic acids of 100 different types and proteins of 100 different types can be separated and detected.
Claim 25 described in Patent Document 1 states: “Each of said groups of said fluorescent particles is further determined by its size and shape.” In addition, paragraph 0037 of Patent Document 1 states that each of the size and the shape can be used as an additional parameter for recognizing a microbead. In connection with this, “Multifunctional encoded particles for high-throughput bio-molecule analysis,” Science 2007, Vol. 315, No. 5,817, p. 1,393-6 (herein after referred to as Non-Patent Document 1) discloses a method for creating a number of microbeads with shapes different from each other by adoption of a lithography technique on a flow path. In accordance with this method, it is possible to create microbeads with an extremely large number of shapes exceeding 1,000,000 types of shape.